Patent Document 1 discloses a relay that includes a relay case containing an electromagnet and a contact part, wherein the relay case is configured to form heat radiation panels at its ceiling apart from the contact part in order to suppress dew condensation from occurring at the contact part. This configuration sets the ceiling of the relay case lower in temperature than a vicinity of the contact part, and thereby makes moisture inside the relay case condense at the ceiling instead of the contact part.
Patent Documents 2 discloses, as a conventional art, a relay configured such that a top face of a relay case is in contact with a chassis of a vehicle via a thermal conductive sheet for outwardly radiating heat generated inside the relay while the relay is ON.
When an electronic control device whose relay is electrically connected to a connector terminal via a wiring route such as a bus bar is used in an extremely cold area, the connector terminal is cooled by outside air after a stop of device operation, and draws heat from a contact part of the relay, and causes the contact part to undergo a sudden drop in temperature. Thus, even in a configuration that a relay case is partially cooled as in Patent Document 1 or 2, a contact part is liable to antecedently drop in temperature and undergo dew condensation.